Woven flat conductor

ABSTRACT

A woven flat cable. The cable is woven with a warp consisting solely of conductors. The conductors are fed through a warp feeding unit to be woven on a shuttle, needle or other loom under constant tension. Each cable may comprise diverse conductors, may be woven differently and may be printed after it is woven.

United States Patent 15] 3,654,383 Copp 1451 Apr. 4, 1972 [54] WOVENFLAT CONDUCTOR 3,257,500 6/1966 Rusch, Jr. et al. ..174/117 x [72]Inventor: Albert R. Copp, Hudson, Mass. O H pUBLICATIONS I731 Assignsurprenam, Jamey FRC- FAB-Rl-CABLE/COMPUTER Woven Ribbon Cable, 22Filed: June 26, 1970 The Zipperwbins PP 50,227 Primary Examiner-LaramieE. Askin Assistant ExaminerA. T. Grimley 52 us. Cl. ..174/117 F,174/112, 139/425 R Arwrneycesari and McKelma [51] Int. Cl. ..H01b 7/08[58] FieldofSearch ..l74/l17R, 112, 115, 117 F, ABSTRACT 174/117 1 17 72113 R; A woven flat cable. The cable is woven with a warp consistingsolely of conductors. The conductors are fed through a warp [56] Ref ec" d feeding unit to be woven on a shuttle, needle or other loom 8 eunder constant tension. Each cable may comprise diverse con- UNITEDSTATES PATENTS ductors, may be woven differently and may be printedafter it is woven. 3,197,554 7/1965 Baker ..174/l12 3,495,025 2/1970Ross 1 74/1 12 X 7 Claims, 4 Drawing Figures I I I I I Q 1 I l T l l l 1y 111' I I l l 4 i 1 i I I E I F I 1 1 1 I l l I I l l I PATENTEDAPR41972 3,654. 381

SHEET 1 OF 2 INVENTOR ALBERT F? COPP ATTORNEY PATENTEDAPR 4 1972 SHEET 2OF 2 INVENTOR ALBERT R. COPP ATTORNEY BACKGROUND OF THE INVENTION Thisinvention generally relates to cables comprising conductors and morespecifically to woven flat cables.

In accordance with conventional weaving techniques, first threads, knownas warp threads are individually fed through eyelets or heddles mountedon one of several movable frames or harnesses. All warp threads are keptunder tension during the weaving process. Each harness can separate thewarp threads threaded through heddles on that harness from the remainingwarp threads by being displaced from the other harness transversely tothe warp threads. The separated warp threads constitute a shed. After asingle harness or combination of harnesses make a shed, a weft thread iscarried through the shed between the separated warp threads. Then theharnesses move and change the shed to weave the weft thread into thewarp.

Weft threads are carried through the shed differently on differentlooms. With a shuttle loom, apparatus throws a shuttle through the shedto position a single weft thread between the separated warp threads eachtime the harnesses change the shed. The shuttle traverses the warp inalternate directions after each shed is made.

A needle loom has a carrier. The shed from a first edge of the warp,known as a selvage, with a weft thread and retracts after the weftthread is caught by apparatus at the second selvage. Each carrieroperation disposes a double weft strand in the shed. This carriersequence follows each shed change.

These weaving techniques are used to manufacture flat cables ofelectrical conductors, optical conductors, or hydraulic tubing. In thefollowing description, all these elements are referred to asconductors". In the prior art, the warp comprises parallel textilethreads and conductors. Only the textile threads are actively involvedin the weaving process. The conductors are only passively involved; thatis, they are surrounded by the weaving process, but are not a part ofit.

These prior cables pose several manufacturing and installation problems.In manufacturing, the warp threads and conductors must be kept paralleland maintained at different tensions. The process of warping, orthreading, the loom with both threads and conductors can increase thewarping time significantly in certain applications and thus reducemanufacturing efficiency. Also, when the cable is later connected tosome device, some weft thread is removed to facilitate connecting theindividual conductors to the device. In most applications, the resultingloose warp threads are cut manually to avoid damaging the individualconductors. This significantly increases the connection time and thecost of making such a connection.

Therefore, it is an object of this invention to provide a woven flatcable which can be manufactured more efficiently than the prior cables.

Another object of my invention is to provide a fiat woven cable whichsimplifies connection procedures.

carrier passes through the SUMMARY Flat cables woven in accordance withmy invention comprise warp and weft as in prior cables. Unlike the priorcables, however, the warp consists of conductors only. There are noseparate textile warp threads. The weft threads are woven directly intothe conductors to form the final woven cable.

This invention is pointed out with particularity in the appended claims.The above and further objects and advantages of an electrical cableformed in accordance with my invention can be obtained by referring tothe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically illustrates ashuttle loom for weaving cables in accordance with this invention;

FIG. 2 shows a cable woven on a shuttle loom;

FIG. 3 schematically illustrates a needle loom for weaving cables inaccordance with this invention, and

FIG. 4 shows a cable woven on a needle loom.

DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT Prior flat cables woven onconventional textile weaving apparatus include both warp threads andparallel conductors despite the previously described disadvantages.Apparently, it was thought that harness motion alters the warp tensionsufficiently to permit the conductors to undulate if only conductorsform the warp. Therefore, textile warp threads have been incorporated asactive weaving elements because their relative elasticity keeps the warptension relatively constant as the har nesses move. The conductors aremore readily maintained at a constant tension because they are not benttransversely with the warp threads as the sheds are formed and thislargely eliminates undulations in the finished cable.

Other known textile weaving techniques for overcoming tension problemsare not practical when applied to weaving cables with conductors as thewarp. For example, the active length of a textile warp can be increasedto reduce the percentage of warp elongation when sheds are made. If thisapproach is adapted for weaving conductors, a considerable quantity ofexpensive conductor material is lost because the portion of warp threadwhich is not woven increases. Although leaders can be tied to bothconductor ends to eliminate these losses, the costs for individuallytying each warp conductor and leader is prohibitive.

A shuttle loom 10 in FIG. 1 includes a unit for maintaining constantwarp tension and for weaving flat cable in accordance with my invention.The shuttle loom 10 is conventional except as modified by the additionof a warp feeding unit 12. The warp conductors from a supply unit 13pass through the warp feeding unit 12, a harness 14 includingrepresentative heddles 16 and 18 and a harness 20 includingrepresentative heddles 22 and 24. After passing through selectedheddles, the conductors pass through a reed 26 and across a breastbeam28 to a cloth beam 30. Four representative conductors 32, 34, 36 and 38pass through the heddles 16, 22, 18 and 24, respectively.

As previously indicated, the warp feeding unit 12 in FIG. 1 maintainseach conductor under substantially constant tension. There are severaldevices or units which can maintain a substantially constant warptension of conductors as a harness rises. For example, the conductorsmay be fed through pinch rollers. Alternatively, weights may besuspended from warp conductors to compensate for changing harnesspositions. As still another alternative, the warp threads for eachharness may be wrapped on a separate counterweighted supply unit such asthe unit 13. Any of these or other approaches cause the entire warpconductor to extend as the tension tends to increase to thereby keep thewarp conductor tension substantially constant during the weavingprocess.

The conductors are woven into the cable when apparatus (not shown)alternately elevates the harnesses 14 and 20 to form sheds and weftthreads are passed through the shed to traverse the warp. For example,when the apparatus raises the harness 14, the heddles l6 and 18 raisethe warp conductors 32 and 36 to form a shed with the remainingconductors 34 and 38. Once the harness forms a shed, other apparatus(not shown) propels a shuttle 42 through the shed to a receiving member(not shown). As the shuttle passes through the shed, it deposits a weftthread 44. Next the harness 14 drops to its original position and theharness 20 rises, and then other apparatus moves the reed 26 to beat theweft thread 44 against the previously woven cable portion. Then theshuttle 42 returns through the shed in the opposite direction anddeposits another weft thread. With this sequence, known as tabbyweaving, a weft thread travels alternately over and under adjacent warpconductors while adjacent weft threads altemately pass over and under agiven warp conductor.

Other known weaving patterns, such as twill weaves, can be obtained bywarping the loom differently or by altering the harness sequence. FIG. 2shows a section of flat electrical cable woven with a twill weave. Atwill weave produces an overall surface pattern of diagonal lines,usually all running to the left or right and made by floating weftthreads 46 over groups of two or more warp threads 48 and staggering thefloats.

As is immediately evident, the warp consists only of the conductors 48;so the warping and connection procedures are simplified and theattendant expenses reduced. As no textile threads are in the warp, theconductor insulation can be removed automatically. Further, if theconductors must be separated, it is merely necessary to remove a portionof the weft thread 46 from the cable.

Although flat cables can be woven successfully on shuttle looms, certainsteps may be required to prevent the weft from unravelling. As will beapparent from FIG. 2, the entire weft thread can be unravelled merely bypulling on either end of the weft thread. If the cable is to bejacketed, the jacket prevents unravelling Other alternatives are alsoavailable; however, whenever weft unravelling is a problem, I prefer toweave the cable on a needle loom.

FIG. 3 schematically shows a needle loom in which a warp feeding unit76, which is similar to the warp feeding unit shown in FIG. 1, carriesfour representative warp conductors 80, 82, 84 and 86. These warpconductors enter the warp feed unit 76 from a supply unit (not shown).Of the four representative conductors, conductors 80 and 84 pass throughheddles 87 and 88 mounted on a harness 89. Conductors 82 and 86 passthrough heddles 94 and 96 on harness 98. All the conductors pass througha reed 100, and weft threads are woven into the warp between the reed100 and a breastbeam 101. During the weaving process, the warp feedingunit 76 maintains the warp conductors under constant tension.

After the harnesses 89 and 98 form a shed, apparatus (not shown) moves acarrier 102 through the shed from a first selvage 103. A typical carrier102 includes hook portion 104, and a weft thread 108 from a spool (notshown) passes through an aperture 106 in the hook portion 104.

When the carrier 102 is fully extended through the warp, the weft thread108 forms a loop 112 around a latch needle 114 at a second selvage. Thelatch needle 114 includes a hook 116 and a latch 118 and moves parallelto the selvage 115. When the carrier 102 retracts, the loop 112 wrapsaround the needle between the hook 116 and latch 118 so the latch needle114 holds the weft thread in position at the selvage 115. As the carrier102 continues retracting, additional weft thread is deposited in theshed so two weft threads are woven into the warp when the harnesses formanother shed.

Before the next double weft strand is pulled through the shed, the latchneedle 114 extends and the loop 112 slides away from the hook 116 andopens the latch 118. Then another loop 120, shown in phantom, is formedaround the latch needle 114. When the latch needle 114 retracts, itcloses the latch 118 and pulls the loop 120 through the loop 112. Thenthe latch 118 opens as the latch needle 114 is extended to engage thenext loop formed in the weft. This sequence of operations produces aregular knitted edge which is easily unravelled from one end only.

FIG. 4 illustrates a preferred weft termination for a cable woven on aneedle loom. This weft termination simplifies steps for connecting thecable to a device. As the cable is being woven, a latch needle 122disposed parallel to a selvage 123 with an initially opened latch 124and a hook 126, passes through a previously formed weft loop 128 and aloop 130 formed by a cord 132. When the hook 126 is fully extended, itengages the cord 132. A weft carrier 134 passes through the shed to aposition shown in phantom and denoted by the reference numeral 134' andthen retracts looping a weft thread 136 around the hook 126. The latchneedle 122 retracts so the loops 128 and 130 engage and close the latch124. As the latch needle 122 continues to retract, it pulls both theweft thread 136 and the cord 132 through the weft loops 128 and 130.These operations repeat and knit the cord 132 into the loops.

Pulling the cord 132 and the weft thread 136 from the last cable end tobe woven unravels the weft thread from the warp. Once the proper amountof weft has been removed, further unravelling is prevented by one of twoprocedures. In a first procedure, the weft thread is pulled generallytransversely to the cable from the other selvage to move the free end ofthe cord 132 through the next weft loop. With the second procedure, thefree end of the cord 132 is pulled back through the preceding loop.Either procedure locks the cord 132 and weft thread 136 to preventfurther unravelling. At the other end of the cable, the weft terminationis cut at the proper position along the warp. Then the weft between thatposition and the other cable end is unravelled back to the end of thecable. The succeeding coil and weft loops lock the remaining cord to aweft thread 136 to prevent unravelling between the ends.

Different looms can produce various cable configurations in accordancewith this invention. The single warp conductors in a cable may actuallycomprise two or more diverse conductors. In FIG. 4, a twisted pair ofconductors constitute one warp conductor 140; a shielded conductor 142is another warp conductor; and single wire conductors 142 and 146 ofdifferent sizes constitute other warp conductors. Furthermore, opticaland electrical conductors or hydraulic tubing can all be combined in asingle cable.

The insulation on the individual conductors shown in FIG. 4 provides theprimary spacing control. The weft threads may vary the spacing to acertain degree by varying the weft thread weight or by changing theweaves. Normally, the weft or weave are constant for a given cable.Therefore, the relative lateral positions for each conductor remainsubstantially fixed to facilitate conductor identification.

It is also possible to weave a flat cable with fastening devices tofacilitate subsequent installation. For example, spaced grommets oreyelets can be woven into the cable during manufacture. Once they arewoven into the cable, the grommets or eyelets can be placed on hooks orpins during installation or otherwise be affixed to supports in thefinal installation.

There are several methods available for identifying individualconductors with my cable because the relative conductor positions areconstant. For example, the weft termination provides identification forcables woven on needle looms. Alternatively, a uniquely color codedselvage can identify all the conductors. Additional color codes may alsobe used. However, color coding may be confusing when a cable comprises alarge number of conductors. This confusion can be overcome by printingnumbers or symbols directly onto the conductor insulation.

In prior cables, a printing head stamps the identification on anindividual conductor before the cable is formed. During the weavingoperation, however, the conductors may twist and obscure theidentification in the cable. My cables, on the other hand, can beprinted after the cable is woven because the improved conductor spacingobtained with these cables substantially eliminates printingregistration problems present in prior cables. An example is shown inFIG. 4 where alternate conductors are printed by transferring a wovencable past a printer. These symbols are always visible because theindividual conductors do not twist after they are woven.

In summary, I form woven cables from electrical or optical conductors orhydraulic tubing which constitute the active warp. It will be obviousthat various weaving methods and apparatus can implement the inventionand that the specific cable construction can vary while the advantagesof this invention are still realized. Therefore, it is the object of theappended claims to cover all such modifications as come within the truespirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A woven cable comprising:

A. at least one warp section, each warp section consisting of warpconductors, and

B. a resilient weft thread woven into said warp conductors,

said weft thread having a transverse dimension significantly less than alike dimension of a warp conductor.

2. A woven cable as recited in claim 1 wherein said conductors compriseelectrical conductors.

3. A woven cable as recited in claim 1 wherein certain of saidconductors include identifying marks spaced along their length.

4. A woven cable as recited in claim 1 including first and secondselvages, said weft thread being woven into said warp at said firstselvage, and forming weft loops at said second selvage, said cableadditionally comprising means for interlocking adjacent of said weftloops.

5. A woven cable as recited in claim 1 including first and secondselvages, the weft thread being woven into said warp at said firstselvage and forming interlocked weft loops at said second selvage.

6. A woven cable comprising:

A. at least one warp section, each warp section consisting of warpconductors, and

B. a resilient weft thread woven into said warp sections, said weftthread having a transverse dimension significantly less than the likedimensions of a warp conductor, said woven cable having first and secondselvages and said weft thread being woven into said warp at said firstselvage and forming interlocked weft loops at said second selvage.

7. A woven cable as recited in claim 6 additionally including separatemeans for interlocking adjacent of said weft loops at said secondselvages.

1. A woven cable comprising: A. at least one warp section, each warp section consisting of warp conductors, and B. a resilient weft thread woven into said warp conductors, said weft thread having a transverse dimension significantly less than a like dimension of a warp conductor.
 2. A woven cable as recited in claim 1 wherein said conductors comprise electrical conductors.
 3. A woven cable as recited in claim 1 wherein certain of said conductors include identifying marks spaced along their length.
 4. A woven cable as recited in claim 1 including first and second selvages, said weft thread being woven into said warp at said first selvage, and forming weft loops at said second selvage, said cable additionally comprising means for interlocking adjacent of said weft loops.
 5. A woven cable as recited in claim 1 including first and second selvages, the weft thread being woven into said warp at said first selvage and forming interlocked weft loops at said second selvage.
 6. A woven cable comprising: A. at least one warp section, each warp section consisting of warp conductors, and B. a resilient weft thread woven into said warp sections, said weft thread having a transverse dimension significantly less than the like dimensions of a warp conductor, said woven cable having first and second selvages and said weft thread being woven into said warp at said first selvage and forming interlocked weft loops at said second selvage.
 7. A woven cable as recited in claim 6 additionally including separate means for interlocking adjacent of said weft loops at said second selvages. 